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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Reports
 Collection: Technical Report Archive and Image Library
Airship model tests in the variable density wind tunnel

Airship model tests in the variable density wind tunnel

Date: January 1, 1932
Creator: Abbott, Ira H
Description: This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of airship models. Eight Goodyear-Zeppelin airship models were tested in the original closed-throat tunnel. After the tunnel was rebuilt with an open throat a new model was tested, and one of the Goodyear-Zeppelin models was retested. The results indicate that much may be done to determine the drag of airships from evaluations of the pressure and skin-frictional drags on models tested at large Reynolds number.
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The drag of two streamline bodies as affected by protuberances and appendages

The drag of two streamline bodies as affected by protuberances and appendages

Date: January 1, 1934
Creator: Abbott, Ira H
Description: This report presents the results of wind tunnel tests of two airship models conducted to determine the drag coefficients at zero pitch, and the effect of fins and cars and of flat and streamlined protuberances located at various positions along the hull. During the investigation the stern of one model was rounded off to produce a blunter shape. The extreme range of the Reynolds number based on the over-all length of the models was from 1,300,000 to 33,000,000. At large values of the Reynolds number the streamlined protuberance affected the drag very little, and the additional drag caused by the flat protuberance was less than the calculated drag by the protuberance alone. The fins and cars together increased the bare-hull drag about 20 per cent.
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Tests in the variable-density wind tunnel of the NACA 23012 airfoil with plain and split flaps

Tests in the variable-density wind tunnel of the NACA 23012 airfoil with plain and split flaps

Date: January 1, 1939
Creator: Abbott, Ira H & Greenberg, Harry
Description: Section characteristics for use in wing design are presented for the NACA 23012 airfoil with plain and split flaps of 20 percent wing chord at a value of the effective Reynolds number of about 8,000,000. The flap deflections covered a range from 60 degrees upward to 75 degrees downward for the plain flap and from neutral to 90 degrees downward for the split flap. The split flap was aerodynamically superior to the plain flap in producing high maximum lift coefficients and in having lower profile-drag coefficients at high lift coefficients.
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Summary of Airfoil Data

Summary of Airfoil Data

Date: January 1, 1945
Creator: Abbott, Ira H; Von Doenhoff, Albert E & Stivers, Louis, Jr
Description: The historical development of NACA airfoils is briefly reviewed. New data are presented that permit the rapid calculation of the approximate pressure distributions for the older NACA four-digit and five-digit airfoils by the same methods used for the NACA 6-series airfoils. The general methods used to derive the basic thickness forms for NACA 6 and 7-series airfoils together with their corresponding pressure distributions are presented. Detail data necessary for the application of the airfoils to wing design are presented in supplementary figures placed at the end of the paper. The report includes an analysis of the lift, drag, pitching-moment, and critical-speed characteristics of the airfoils, together with a discussion of the effects of surface conditions. Available data on high-lift devices are presented. Problems associated with lateral-control devices, leading-edge air intakes, and interference are briefly discussed, together with aerodynamic problems of application. (author).
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Theoretical damping in roll and rolling moment due to differential wing incidence for slender cruciform wings and wing-body combinations

Theoretical damping in roll and rolling moment due to differential wing incidence for slender cruciform wings and wing-body combinations

Date: January 1, 1952
Creator: Adams, Gaynor J & DUGAN DUANE W
Description: A method of analysis based on slender-wing theory is developed to investigate the characteristics in roll of slender cruciform wings and wing-body combinations. The method makes use of the conformal mapping processes of classical hydrodynamics which transform the region outside a circle and the region outside an arbitrary arrangement of line segments intersecting at the origin. The method of analysis may be utilized to solve other slender cruciform wing-body problems involving arbitrarily assigned boundary conditions. (author).
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Investigation of downwash, sidewash, and Mach number distribution behind a rectangular wing at a Mach number of 2.41

Investigation of downwash, sidewash, and Mach number distribution behind a rectangular wing at a Mach number of 2.41

Date: January 1, 1957
Creator: Adamson, David & Boatright, William B
Description: An investigation of the nature of the flow field behind a rectangular wing of circular arc cross section has been conducted in the Langley 9-inch supersonic tunnel. Pitot- and static-pressure surveys covering a region of flow behind the wing have been made together with detailed pitot surveys throughout the region of the wake. In addition, the flow direction has been measured by means of a weathercocking vane. Theoretical calculations have been made to obtain the variation of both downwash and sidewash with angle of attack by using the superposition method of Lagerstrom, Graham, and Grosslight. In addition, the effect of wing thickness on the sidewash with the wing at 0 degree angle of attack has been evaluated.
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Standard nomenclature for airspeeds with tables and charts for use in calculation of airspeed

Standard nomenclature for airspeeds with tables and charts for use in calculation of airspeed

Date: January 1, 1946
Creator: Aiken, William S , Jr
Description: Symbols and definition of various airspeed terms that have been adopted as standard by the NACA subcommittee on aircraft structural design are presented. The equations, charts, and tables required in the evaluation of true airspeed, calibrated airspeed, equivalent airspeed, impact and dynamic pressures, and Mach and Reynolds numbers have been compiled. Tables of the standard atmosphere to an altitude of 65,000 feet and a tentative extension to an altitude of 100,000 feet are given along with the basic equations and constants on which both the standard atmosphere and the tentative extension are based.
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The pack method for compressive tests of thin specimens of materials used in thin-wall structures

The pack method for compressive tests of thin specimens of materials used in thin-wall structures

Date: January 1, 1939
Creator: Aitchison, C S & Tuckerman, L B
Description: The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material. In the pack test an odd number of specimens are assembled into a relatively stable pack, like a "pack of cards." Additional lateral stability is obtained from lateral supports between the external sheet faces of the pack and outside reactions. The tests seems adequate for many problems in structural research.
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Theoretical and experimental investigation of the subsonic-flow fields beneath swept and unswept wings with tables or vortex-induced velocities

Theoretical and experimental investigation of the subsonic-flow fields beneath swept and unswept wings with tables or vortex-induced velocities

Date: January 1, 1957
Creator: Alford, William J , Jr
Description: The flow-field characteristics beneath swept and unswept wings as determined by potential-flow theory are compared with the experimentally determined flow fields beneath swept and unswept wing-fuselage combinations. The potential-flow theory utilized considered both spanwise and chordwise distributions of vorticity as well as the wing-thickness effects. The perturbation velocities induced by a unit horseshoe vortex are included in tabular form. The theoretical predictions of the flow-field characteristics were qualitatively correct in all cases considered, although there were indications that the magnitudes of the downwash angles tended to be overpredicted as the tip of the swept wing was approached and that the sidewash angles ahead of the unswept wing were underpredicted. The calculated effects of compressibility indicated that significant increases in the chordwise variation of flow angles and dynamic-pressure ratios should be expected in going from low to high subsonic speeds.
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Determination of vortex paths by series expansion technique with application to cruciform wings

Determination of vortex paths by series expansion technique with application to cruciform wings

Date: January 1, 1957
Creator: Alksne, Alberta Y
Description: A series method of determining two-dimensional vortex paths is considered and applied to the computation of vortex positions behind a slender equal-span cruciform wing at any angle of bank as a function of the distance behind the trailing edge. Calculated paths are shown for four bank angles. For a bank angle of 45 degrees comparison is made with the results of a closed expression given in NACA-TN-2605. For other bank angles water-tank experiments provide qualitative comparison. Satisfactory agreement is found for a sufficient distance downstream to include most practical missile-tail positions. The interference forces on an equal-span cruciform wing are calculated for five angles of bank (including the trivial case of zero bank) from the vortex positions found by use of the series.
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